Summary:
Add two type aliases for Cache: BlockCache and GeneralCache, and add LRUCacheOptions::MakeSharedGeneralCache(). This will ease upgrade to an intended future change to separate the cache API between block cache and other (general) uses, including row cache. Separating the APIs will make it easier to expose more details of block caching for customization. For example, it would be nice to pass the file unique ID and offset as the logical cache key instead of using a Slice, which could facilitate some file-specific customizations in block cache. This would also make it clear that HyperClockCache is not usable as a general cache, because it can only deal with fixed-size block cache keys.
block_cache, row_cache, and blob_cache are the uses of Cache in the public API. blob_cache should be able to use BlockCache while row_cache is a GeneralCache user, as its keys are of arbitrary size.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11450
Test Plan: see updated unit test.
Reviewed By: anand1976
Differential Revision: D45882067
Pulled By: pdillinger
fbshipit-source-id: ff5d9f0b644f87ae337a29a7728ce3ed07b2a4b2
Peter Dillinger
4067acabca